Well, one thing I would definitely include for a poly household: top notch sound proofing on all the bed rooms.
But I'm not sure I understand how else a polyamorous dwelling would differ from a regular dwelling. Poly people, like mono people, need their personal space, usually in the form of their own bedroom. If I had three poly people living in a household, I would probably want three separate bedrooms, plus bedrooms for any kids who live with us. In that sense, it's no different than any modern 3 or 4 bedroom home.
This is all a bit idealistic, though... Polys break up and move out just as often as monos. How do you create flexibility for people to come & go as relationships grow and decay? How do you address the variety of configurations?
And I'm just going to say it: Poly people seem to have more than the usual drama. If I knew there was a building full of poly people, I would most likely avoid it. Oh, I might hang around outside and see if anyone cute comes out, maybe ask them out for coffee.. but I would never move in there. It would be worse than a sorority house!!
I don't need labels to define me. They're sticky and I hate the glue they leave behind.